Understanding electron transport, dissipation, and fluctuations at sub-micron length scales is critical for the continued miniaturization of electronic and optical devices, as well as atom and ion traps, and for the electrical control of solid-state quantum circuits. While it is well-known that electronic transport in small samples defies the conventional wisdom associated with macroscopic devices, resistance-free transport is difficult to observe directly. Most of the measurements demonstrating these effects make use of Ohmic contacts attached to sub-micron scale samples and observe quantized but finite resistance corresponding to the voltage drop at the contact of such a system with a macroscopic conductor. Techniques for non-invasive probing of electron transport are required because they can provide insights into electronic dynamics at small length scales.